Study of capacity fade of lithium-ion polymer rechargeable batteries with continuous cycling

A cycle life study was done on commercial lithium-ion polymer batteries to quantify contributions to capacity fade with continuous charge-discharge cycling. The cell consists of graphite (meso-carbon microbeads) as an anode material and lithium cobalt oxide (Li_xCoO₂) as a cathode material. Analyses were done using ac impedance spectroscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The results show that contributions to capacity fade with continuous charge/discharge cycling included solvent-salt deposition on the anode surface; however, instability and cation disorder in the cathode electrode were identified as the main reasons for capacity fade with continuous charge/discharge cycling.